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Dehydrated drivers make the same number of mistakes as drink drivers

A Loughborough University study has revealed that even mild dehydration is equivalent to being over the drink driving limit in terms of driver errors.

Researchers at Loughborough University carried out a range of tests over two days on male drivers, using a laboratory-based driving simulator. During the normal hydration test there were 47 driving incidents, but when the men were dehydrated that number more than doubled to 101 – a similar number to what might be expected of someone driving under the influence of drugs or alcohol. These included lane drifting, late braking and touching or crossing the rumble strip or lane line.

Professor Ron Maughan, Emeritus Professor of Sport and Exercise Nutrition at Loughborough University and Chair of the European Hydration Institute Science Advisory Board led the study. He said: “We all deplore drink driving, but we don't usually think about the effects of other things that affect our driving skills, and one of those is not drinking and dehydration.

“There is no question that driving while under the influence of drink or drugs increases the risk of accidents, but our findings highlight an unrecognised danger and suggest that drivers should be encouraged to make sure they are properly hydrated.

“To put our results into perspective, the levels of driver errors we found are of a similar magnitude to those found in people with a blood alcohol content of 0.08%, the current UK legal driving limit. In other words drivers who are not properly hydrated make the same number of errors as people who are over the drink drive limit.”

With driver errors accountable for 68% of all vehicle crashes in the UK, the European Hydration Institute, who sponsored the research are urging drivers to be cautious and ensure they are adequately hydrated before setting off on journeys, especially during the warmer summer months. The level of dehydration induced in the study was mild and could easily reflect that of individuals with limited access to fluid over a busy working day.

Jane Holdsworth, Director of the European Hydration Institute (EHI), said “Anecdotal evidence suggests that many drivers avoid drinking on long journeys to minimise bathroom stops, yet we know that even mild hydration can cause symptoms such as headache, tiredness and lethargy. Driver error is by far the largest cause of road traffic accidents and the EHI wanted to test whether mild hydration had an impact on the incidence of common driver errors.”

The research has been published in the medical journal Physiology and Behaviour.

Notes for editors

Press release reference number: PR 15/54

About the study

The study was led by Phillip Watson, Andrew Whale, Stephen A. Mears, Louise A. Reyner and Ronald J. Maughan from the School of Sport, Exercise and Health Sciences at Loughborough University. Their paper was published online in Physiology and Behaviour on Sunday 19th April 2015.

Each volunteer visited the laboratory on three separate occasions and used the simulator while normally hydrated and on a dry day. On one day the men were provided with 200ml of fluid every hour and, on the dehydration test day, only 25ml of fluid per hour.

The simulated driving task included a two hour continuous monotonous drive on a dual carriageway, with bends, a hard shoulder and simulated auditory ‘rumble strips’, and slow moving vehicles which had to be overtaken.

About Loughborough University

Loughborough is one of the country’s leading universities, with an international reputation for research that matters, excellence in teaching, strong links with industry, and unrivalled achievement in sport and its underpinning academic disciplines.

It has been awarded five stars in the independent QS Stars university rating scheme, putting it among the best universities in the world, and was named Sports University of the Year 2013-14 by The Times and Sunday Times. Loughborough is consistently ranked in the top twenty of UK universities in the Times Higher Education’s ‘table of tables’ and has been voted England's Best Student Experience for six years running in the Times Higher Education league. In recognition of its contribution to the sector, Loughborough has been awarded seven Queen's Anniversary Prizes.

In 2015 the University will open an additional academic campus in London’s new innovation quarter. Loughborough University in London, based on the Queen Elizabeth Olympic Park, will offer postgraduate and executive-level education, as well as research and enterprise opportunities.

About the European Hydration Institute

The European Hydration Institute stresses the importance and many health benefits of being properly hydrated and provides information to help people understand how best to do this in different situations on its website: www.europeanhydrationinstitute.org/esThe European Hydration Institute (EHI) is a foundation established with the objectives of advancing and sharing knowledge and understanding of all matters relating to human hydration and the effects of hydration on health, wellness and physical and cognitive performance. The EHI was founded in response to the need expressed by a number of scientists, nutritionists, dieticians and health care professionals, for a one stop shop relating to hydration where: All hydration science and knowledge could come together; strategies for further advancing understanding in the area of hydration could be developed and support for efforts designed to ensure people across Europe are properly hydrated could be provided